Field of the Invention
The invention relates to a display apparatus, and more particularly to a touch display panel and a fabrication method thereof.
Description of Related Art
A touch display panel may be disposed in a mobile electron apparatus for providing a display function and a touch control function. In some products, a pressure sensor may be additionally disposed under the touch display panel for providing a pressure sensing function. FIG. 1 is a sectional-view diagram of a conventional electronic apparatus 100 with a pressure sensing function. The conventional electronic apparatus 100 includes a display panel 110, a backlight module 120 and a pressure sensor 130. The display panel 110 has a top substrate 111, a liquid crystal layer 112 and a bottom substrate 113. The liquid crystal layer 112 is disposed between the top substrate 111 and the bottom substrate 113. The backlight module 120 is stacked under the display panel 110. The backlight module 120 provides a backlight source to the display panel 110, and the liquid crystal display panel 110 displays an image.
The pressure sensor 130 is stacked under the backlight module 120. There is a cell gap (having a distance of an interval L1) between the pressure sensor 130 and the backlight module 120. The backlight module 120 may serve as an electrode plate of a parasitic capacitor C1, and the pressure sensor 130 may serve as another electrode plate of the parasitic capacitor C1. In a situation that a pressure 10 is not yet applied to the display panel 110, the interval L1 between the pressure sensor 130 and the backlight module 120 remains unchanged. When the pressure 10 is applied to the display panel 110, the display panel 110 and the backlight module 120 are deformed, such that the interval L1 becomes smaller (i.e., a capacitance of the parasitic capacitor C1 becomes greater). The pressure sensor 130 senses a change amount of the capacitance of the parasitic capacitor C1. The change amount of the capacitance of the parasitic capacitor C1 may be used to estimate a size of the pressure 10. Because a specific interval L1 (for accommodating the deformation of the backlight module 120) has to be kept between the additionally disposed pressure sensor 130 and the backlight module 120, the thickness of the conventional electronic apparatus 100 is increased due to the additionally disposed pressure sensor 130 and the interval L1.